Head north out of Sydney’s CBD over the Sydney Harbour Bridge and you’ll quickly find yourself in the delightful, upmarket suburb of Northbridge, which lies east of the Warringah freeway and slopes down to Long Bay and Sailors Bay on Middle Harbour. Stand on the heights here at Northbridge, or wander down to the harbour shores and, especially at weekends, you’ll see fleets of yachts - powered by sails of every imaginable colour - dodge and weave among the power boats, jet skis, ferries and skiffs in the deep blue waters. This part of the harbour, in fact, is the ideal platform from which you can see how the other half lives in multi-levelled homes of every conceivable design clinging limpet-like to the sandstone cliffs which rear up from the sea. The ridges are occupied by more conventional mansions. Regarded as one of Sydney's engineering marvels when it was completed by a developer intent on opening up land beyond Flat Rock Creek Gorge in the 1890s, the suspension bridge between Cammeray and Northbridge is still much admired. The bridge's ornately crenallated towers are more suggestive of a medieval castle than a gorge-crossing in the New World.